A nanocomposite precursor strategy to mixed-metal oxides with excellent catalytic activity for thermal decomposition of ammonium perchlorate

摘要

NiAl-layered double hydroxide/carbon (LDH/C) nanocomposites were prepared by a hydrothermal process simultaneously involving the crystallization of LDH and carbonization of glucose. The nanocomposites calcined in air lead to porous NiAl-mixed-metal oxides with tunable surface areas. The porosity of resultants is ascribed to the templating effect, resulting from the depletion of carbonaceous products with the elevating temperature under air atmosphere. The specific surface areas of products are sensitive to carbonaceous product content in the composite precursor, Ni/Al ratio and as well the calcination temperature. The specific surface area reaches a maximum under medium carbon content in the precursor and decreases with the increasing calcination temperature. On a basis of the nature of metal oxides and their high surface areas, the mixed-metal oxides are utilized for catalytic thermal decomposition of ammonium perchlorate (AP) and exhibit excellent catalytic activity. The peak temperature of AP decomposition was greatly decreased compared to that of pure AP. And the temperature is strongly dependent on the surface areas of mixed oxides. Furthermore, the decomposition activation energy of AP with the mixed oxide additives was calculated to be 74.6 and 80.4 kJ mol~(-1) by two methods of kinetics, respectively, both of which are smaller than that of pure AP.